Smoke Detector Fire Alarm Wireless + 9V Battery

Features: Independent installation on ceilings and walls, with mounting bracket, which is easy to install and do not need to debug. With specially designed cover, can protect it from dust. Built-in dedicated IC: with stable performance and high sensitivity. Can monitor air and detect smoke with optical principles. When it reaches the maximum amount that the chamber can bear, it will alert. LED light flash indicator. With a test button: can take analog alarm tests of the smoke alarm. Can warn and alert people to stay far away from dangerous field when it detects smoke. Suitable for use in house, shop, school, office building, storage areas, etc. 
Specifications: Color: white Material: ABSPower supply: 9V battery Standby current: 10ŒºAAlarm current: ‚ 15 Operating voltage: DC9V Alarm indication: red LED flash & sound Loudness: ‚ 120dB Operating temperature: -10 degrees centigrade to +50 degrees centigrade Operating humidity: ‚ 95%RH (40¬±2 degrees centigrade)Detecting area: 60 sqm Item size: 3.4 * 10.7cm/ 1.3 * 4.2in (diameter)Item weight: 100g/ 3.5oz Package size: 10.5 * 10.5 * 4cm/ 4.1 * 4.1 * 1.5in Package weight: 101g/ 3.56oz 
Packing list: 1 * Smoke alarm 1 * 9V Battery1 * Bag of screws 1 * User manual.